8-3 
On Irrigation in Tasmania. 
lias lately been constructed. From this, on the south 
side, a channel, 12 yards broad at the head and 10 or 12 
feet deep, leads a portion of the water for a distance of 
about 30 miles; and from the north side two channels 
are cut. One of these is lately made, being 12 yards broad 
and 16 feet deep, and conveying water to a distance of 
45 miles : the other is an ancient work ; it is 25 yards 
broad, and 12 or 14 feet deep at its head, and terminates 
at the distance of 15 miles in a tank or reservoir entirely 
artificial, and formed by an earthen embankment 12 
miles long, with many vast sluices of granite in it. The 
tank when full is 2J miles broad in the widest part, and 
25 miles in circumference, and is capable of containing 
100,000,000 of cubic yards of water. 
In the Cuddapah district are many vast tanks : one 
of these has an embankment 600 yards long, 30 yards 
thick at top, and 130 yards at bottom, the inner slope 
being entirely lined with large blocks of stone. This tank 
when full is about 12 or 15 miles in circumference. 
The effect of irrigation in these districts is such, that 
good land, paying a tax of 3s. an acre, and saleable at 
8s. per acre, will, when watered, pay a tax of 12s. per 
acre, and be saleable at 40s.; and land so poor as to be 
totally unfit for cultivation when not artificially irrigated, 
will, when watered, be immediately saleable at 30s. 
an acre, besides paying a tax of 8s. or 10s. Lands so 
watered, even such as would be totally worthless without 
irrigation, bear a white crop annually for centuries 
without any manure whatever. Indeed it is certain that 
in those latitudes in which the sun has some power, water 
alone is required to make almost any land, however poor 
naturally, capable of bearing a constant succession of 
crops. Tracts of land incapable of providing sustenance 
for man will, when irrigated, bear 20 to 25 bushels of 
g 2 
